Coating compositions for providing water and blister resistance to ink-receptive paper

Abstract

A paper coating composition is described, containing a pigment and an aqueous binder as major components, and further containing a thermosetting resin in aqueous solution, obtained by reacting or mixing (Y) a water-soluble resin obtained by reacting urea, polyalkylenepolyamine, and dibasic carboxylic acid and reacting the resulting polyamidopolyurea with formaldehyde, (a) at least one alkylenediamine or polyalkylenepolyamine, and (b) epihalohydrin, or the reaction product between (Y) and (b) with (a).

What is claimed is: 
     
       1. A paper coating composition containing a pigment and an aqueous binder as major components, and further containing a thermosetting resin in aqueous solution, obtained by reacting or mixing (Y) a water-soluble resin obtained by reacting urea, polyalkylenepolyamine, and dibasic carboxylic acid to form a polyamidopolyurea and reacting the resulting polyamidopolyurea with formaldehyde, (a) at least one alkylenediamine or polyalkylenepolyamine, and (b) epihalohydrin, or the reaction product between (Y) and (b) with (a). 
     
     
       2. A composition as in claim 1, wherein said water-soluble resin (Y) is a water-soluble resin obtained by a deammoniation reaction between urea and polyalkylenepolyamine, then a dehydration condensation between the reaction product and dibasic carboxylic acid, and a deammoniation reaction between the resulting product and urea, and a reaction of the thus obtained polyamidopolyurea with formaldehyde in an aqueous solution under an acidic condition, or initially under an alkaline condition and then under an acidic condition. 
     
     
       3. A composition as in claim 1, wherein said water-soluble resin (Y) is a water-soluble resin obtained by a dehydration condensation between polyalkylenepolyamine and dibasic carboxylic acid, then a deammoniation reaction between the reaction product and urea, and a reaction of the thus obtained polyamidopolyurea with formaldehyde in an aqueous solution under an acidic condition, or initially under an alkaline condition and then under an acidic condition. 
     
     
       4. A composition as in claim 2, wherein from 1.5 to 2.5 moles of polyalkylenepolyamine per mole of urea is used in the reaction between urea and polyalkylenepolyamine, and subsequently dibasic carboxylic acid is used in an amount of from 0.3 to 0.7 mole per mole of the polyalkylenepolyamine, and subsequently urea is used in an amount of from 0.2 to 1.5 moles per mole of secondary amino group in the polyalkylenepolyamine. 
     
     
       5. A composition as in claim 2, wherein the temperature during the reaction between urea and polyalkylenepolyamine is maintained at from 100° to 200° C., the temperature during the reaction between the resulting product and dibasic carboxylic acid is maintained at from 120° to 250° C., and the temperature during the reaction between the resulting product and urea is maintained at from 100° to 180° C. 
     
     
       6. A composition as in claim 3, wherein from 1.4 to 3.0 moles of polyalkylenepolyamine is used per mole of dibasic carboxylic acid in the reaction between the dibasic carboxylic acid and the polyalkylenepolyamine, and the amount of urea used is from 0.2 to 1.0 mole per mole of the amino group of polyalkylenepolyamine. 
     
     
       7. A composition as in claim 3, wherein the temperature during the reaction between the dibasic carboxylic acid and the polyalkylenepolyamine is maintained at from l20° to 250° C., and the temperature during the reaction between the resulting product and urea is maintained at from 100° to 180° C. 
     
     
       8. A composition as in claim 1, wherein the amount of formaldelyde is from 0.2 to 1 mole per mole of the total amount of urea used for synthesizing the polyamidopolyurea. 
     
     
       9. A composition as in claim 1, wherein the temperature during the reaction between formaldehyde and polyamidopolyurea is maintained at from 40° to 80° C. 
     
     
       10. A composition as in claim 1, wherein the amount of (a) is from 0.1 to 3 moles per mole of the dibasic carboxylic acid used for synthesizing (Y). 
     
     
       11. A composition as in claim 1, wherein the amount of (b) is from 0.1 to 4 moles per mole of (a). 
     
     
       12. A composition as in claim 1, wherein the temperature during the simultaneous reaction of (Y), (a), and (b) is maintained from 30° to 80° C. 
     
     
       13. A composition as in claim 1, wherein the temperature of the reaction between (Y) and (b) is 30° C. to reflux temperature, and the temperature of the reaction between the resulting product and (a) is 30° to 100° C. 
     
     
       14. A composition as in claim 1, wherein the polyalkylenepolyamine is a compound having two primary amino groups and at least one secondary amino group per molecule. 
     
     
       15. A composition as in claim 1, wherein said dibasic carboxylic acid is an aliphatic dibasic carboxylic acid. 
     
     
       16. A composition as in claim 1, wherein the solids content of the aqueous binder is from 3 to 30 wt% based on the weight of pigment. 
     
     
       17. A composition as in claim 1, wherein the solids content of the thermosetting resin obtained from (a), (b), and (Y) is 0.05 to 5 wt%, based on the weight of the pigment. 
     
     
       18. A composition as in claim 1, which contains from 30 to 80 wt% solids. 
     
     
       19. A process for preparing a thermosetting resin in aqueous solution, comprising simultaneously reacting (Y) a water-soluble resin obtained by reacting urea, polyalkylenepolyamine, and dibasic carboxylic acid, and further reacting the resulting polyamidopolyurea with formaldehyde, (a) at least one alkylenediamine or polyalkylenepolyamine, and (b) epihalohydrin, or reacting the reaction product between (Y) and (b) with (a). 
     
     
       20. A coated paper having coated thereon a paper coating composition described in claim 1.